STANDARD	  RUPTURE	  FORMAT	  Version	  2.0	  	  Robert	  Graves	  12/02/2014	  	  Introduction	  	  The	  Standard	  Rupture	  Format	  (SRF)	  is	  an	  ASCII	  based	  file	  format	  that	  provides	  a	  complete	  kinematic	  description	  for	  earthquake	  ruptures.	  	  The	  general	  fault	  surface	  is	  represented	  by	  a	  distribution	  of	  point	  sources	  (subfaults).	  	  Each	  point	  source	  description	  contains	  all	  the	  necessary	  kinematic	  information	  to	  compute	  the	  contribution	  of	  that	  subfault	  to	  the	  total	  response	  of	  the	  fault	  rupture.	  	  In	  principle,	  there	  is	  no	  inherent	  restriction	  on	  the	  geometry	  of	  the	  fault	  surface	  or	  on	  the	  spacing	  and	  distribution	  of	  the	  point	  sources	  used	  to	  describe	  the	  fault	  surface.	  	  However,	  it	  is	  recognized	  that	  most	  current	  methods	  used	  to	  develop	  or	  model	  fault	  ruptures	  are	  based	  on	  descriptions	  that	  employ	  planar	  rectangular	  segments.	  To	  facilitate	  the	  exchange	  (and	  retention)	  of	  fault	  representations	  in	  this	  format,	  the	  description	  presented	  below	  allows	  for	  the	  (optional)	  inclusion	  of	  information	  that	  specifies	  the	  planar	  segments	  used	  to	  define	  the	  fault	  surface.	  	  Aki	  &	  Richards	  convention	  for	  strike,	  dip	  and	  rake	  are	  used	  for	  all	  the	  source	  descriptions.	  	  Slip	  is	  specified	  in	  three	  orthogonal	  directions,	  two	  within	  the	  subfault	  surface,	  and	  the	  third	  in	  the	  direction	  of	  the	  outward	  normal	  to	  that	  surface.	  	  This	  allows	  for	  the	  possibility	  of	  time	  dependent	  rake	  and/or	  fault	  opening.	  	  Figure	  1	  illustrates	  the	  coordinate	  system	  conventions	  used	  in	  this	  description.	  

Figure 1: Coordinate system conventions for anindividual subfault. The system (x, y, z) is the global
system (e.g., x = north, y = east, z = down). The
system (u1, u2, u3) is the local system in which the slip
is specified. The axes u1 and u2 are tangent to therupture surface and u3 is the outward normal to thesurface. The strike (φ), and dip (δ) are the same as Aki& Richards. Strictly speaking, the rake (λ) defines theoorientation of the u1 axis (with u2 at λ+90 ).	  
For	  a	  pure	  shear	  dislocation	  with	  constant	  rake,	  all	  slip	  will	  be	  in	  the	  u1	  direction.	  	  Incorporating	  time	  variable	  rake	  is	  handled	  using	  two	  orthogonal	  components	  (u1	  and	  u2)	  each	  with	  a	  unique	  slip-­‐rate	  function.	  	  In	  this	  case	  λ	  can	  be	  specified	  such	  that	  u1	  and	  u2	  bracket	  the	  average	  rake	  direction.	  	  Version	  2.0	  Format	  Specification	  	  The	  file	  type	  as	  described	  below	  is	  in	  ASCII	  format	  to	  allow	  for	  easy	  exchange	  and	  editing	  capabilities.	  	  The	  general	  file	  format	  is	  as	  follows:	  	  VERSIONHEADER BLOCK (optional)
DATA BLOCK	  where	  	  VERSIONHEADER BLOCKDATA BLOCK

version identifier (e.g., 2.0)
comments and general fault description
detailed information for all point sources covering fault surface	  	  HEADER BLOCK	  The	  optional	  HEADER BLOCK	  consists	  of	  a	  series	  of	  lines	  describing	  the	  general	  features	  of	  the	  rupture	  and	  fault	  surfaces.	  	  Comment	  lines	  are	  permitted	  in	  the	  HEADER BLOCK	  and	  are	  denoted	  by	  the	  ‘#’	  character	  appearing	  at	  the	  beginning	  of	  the	  line.	  	  Following	  the	  comment	  lines,	  an	  optional	  description	  for	  one	  or	  more	  planar	  segments	  representing	  the	  fault	  can	  appear.	  	  Additional	  descriptive	  formats	  can	  be	  developed	  and	  added	  as	  needed.	  	  For	  the	  planar	  segment	  format,	  the	  first	  line	  is:	  	  PLANE

NSEG

PLANE
NSEG

flag specifying that following lines describe planar fault
total number of segments in fault description	  where	  	  	  Then	  for	  each	  fault	  segment,	  the	  following	  two	  lines	  are	  needed:	  	  
ELON
STK

ELAT
DIP

NSTK
DTOP

NDIP
SHYP

LEN
DHYP

WID	  
where	  (for	  this	  segment)	  	  ELON
ELAT
NSTK
NDIP
LEN

top center longitude
top center latitude
number of point sources (subfaults) along strike
number of point sources (subfaults) down-dip
segment length (km)

WID
STK
DIP
DTOP
SHYP
DHYP

segment width (km)segment strike
segment dip
depth to top of fault segment (km)along strike location (from top center) of hypocenter for this segment (km)down-dip location (from top edge) of hypocenter for this segment (km)	  The	  above	  description	  is	  repeated	  for	  each	  additional	  segment,	  up	  to	  the	  total	  of	  NSEG.	  	  Here	  is	  an	  example	  description	  for	  a	  3	  segment	  fault:	  	  PLANE 3-119.0985
95
40-118.9582
4980-118.6702
210
75

35.0140
3.00
35.1398
0.00
35.23180.00

2-2.003-15.00
410.00216.0010.00
230.0010.00
220.00
12.00

12.00
18.00
15.00	  	  DATA BLOCK	  Following	  the	  optional	  header	  lines	  described	  above	  are	  the	  required	  DATA BLOCK	  lines.	  	  The	  DATA BLOCK	  consists	  of	  one	  or	  more	  POINT BLOCK	  structures.	  	  Strictly	  speaking,	  only	  one	  POINT BLOCK	  structure	  is	  required,	  and	  it	  can	  contain	  the	  information	  for	  all	  of	  the	  point	  sources	  covering	  the	  fault.	  	  However,	  the	  use	  of	  multiple	  POINT BLOCK	  structures	  is	  convenient	  for	  describing	  the	  individual	  segments	  of	  a	  multi-­‐segment	  fault	  rupture	  (i.e.,	  one	  POINT BLOCK	  structure	  for	  each	  segment).	  	  The	  first	  line	  in	  each	  POINT BLOCK	  is:	  	  POINTSNPPOINTS
NPflag specifying that following lines describe point sources (subfaults)
number of point sources (subfaults) to follow	  where	  	  	  Following	  this	  are	  blocks	  of	  lines	  containing	  information	  about	  each	  of	  the	  NP	  point	  sources	  (subfaults).	  	  The	  format	  of	  the	  lines	  in	  each	  of	  these	  NP	  blocks	  is:	  	  
LON
RAKESR1[1]
SR2[1]
SR3[1]	  where	  LATSLIP1SR1[2]
SR2[2]
SR3[2]DEP
NT1
SR1[3]SR2[3]SR3[3]

STK
DIP
AREA
SLIP2NT2
SLIP3. . . SR1[NT1]. . . SR2[NT3]. . . SR3[NT3]

TINIT
NT3DT

VSDEN	  
LONlongitude of subfault center
LAT
latitude of subfault center
DEP
depth of subfault center (km)STK
strike
DIP
dip
AREA
area of subfault (cm2)
TINIT
initiation time when rupture reaches subfault center (sec)DTtime step in slip velocity function (sec)VSshear wave velocity at source point (cm/sec), enter -1 if not known
DENdensity at source point (g/cm3), enter -1 if not known
RAKE
direction of u1 axis (rake direction)
SLIP1
total slip in u1 direction (cm)NT1number of time points in slip rate function for u1 direction
SLIP2
total slip in u2 direction (cm)NT2number of time points in slip rate function for u2 direction
SLIP3
total slip in u3 (surface normal) direction (cm)NT3number of time points in slip rate function for u3 direction
SR1[1],…,SR1[NT1]slip rate at each time step for u1 direction (cm/sec)
SR2[1],…,SR2[NT2]slip rate at each time step for u2 direction (cm/sec)
SR3[1],…,SR3[NT3]slip rate at each time step for u3 direction (cm/sec)

	  Although	  the	  general	  format	  given	  here	  allows	  for	  slip	  in	  all	  three	  directions	  (u1,	  u2,	  u3),	  most	  cases	  will	  have	  only	  one	  (u1)	  or	  two	  (u1,	  u2)	  non-­‐zero	  slip	  components.	  	  In	  these	  situations,	  the	  remaining	  slip	  components,	  as	  well	  as	  the	  number	  of	  time	  points	  for	  the	  slip	  rate	  function,	  are	  specified	  as	  “0”.	  	  	  Changes	  from	  Version	  1.0	  1. Added	  option	  to	  specify	  comment	  lines	  within	  the	  HEADER BLOCK.	  	  Comment	  lines	  are	  denoted	  with	  a	  leading	  ‘#’.	  
2. Added	  fields	  for	  VS	  (shear	  wave	  velocity	  in	  cm/sec)	  and	  DEN	  (density	  in	  g/cm3)	  to	  the	  subfault	  description.	  	  Values	  for	  these	  parameters	  may	  not	  always	  be	  available	  (e.g.,	  for	  scenario	  ruptures	  generated	  for	  an	  unspecified	  region),	  in	  which	  case	  a	  value	  of	  -­‐1	  should	  be	  entered.	  
3. Added	  option	  to	  subdivide	  the	  specification	  of	  the	  individual	  point	  source	  descriptions	  into	  multiple	  POINT BLOCK	  structures	  (version	  1.0	  requires	  that	  the	  subfault	  descriptions	  for	  all	  fault	  segments	  be	  included	  in	  a	  single	  POINT BLOCK	  structure).	  	  	  	  Examples	  	  Example	  1:	  Single	  Point	  Source	  	  2.0## Example 1: This is an example of the simplest form of a SRF file.
## This file represents a point source with strike=291, dip=59 and rake=142.
# Since the source is represented kinematically, it has a slip (16.32 cm)# over an area (2.64926e+11 cm*cm) with rigidity given by Vs*Vs*den# [(3.64e+05 cm/s)*(3.64e+05 cm/s)*(2.67 g/cm^3)=3.54e+11 dyne/cm^2].
# This gives a seismic moment of 1.53e+24 dyne-cm (Mw 5.42).
## The slip-rate function is a simple isosceles triangle discretized at 0.025 sec.
# Note that the slip-rate function is zero for all time points after those# listed in the file (i.e., the last time point is implicitly zero and# is not included).
## Other useful information that might be included in these comment lines is documentation# of the source of the rupture e.g.,##"Example 1 is a sample SRF generated by hand on Fri Nov 21 12:52:16 PST 2014#
(Robert Graves, <rwgraves@usgs.gov>)."## or the usable bandwidth of the rupture, e.g.,##"This model is applicable in the bandwidth T>10 sec."#POINTS 1-117.7610 33.9530 14.70 291 59 2.64926e+11 0.0000 2.50000e-02 3.64000e+05 2.67000e+00
142
16.32
40.00
00.00
00.00000e+00 1.63200e+02 3.26400e+02 1.63200e+02	  Example	  2:	  Single	  Planar	  Fault	  	  2.0## Example 2a: Single planar fault.
## Following these comment lines, a description of the fault plane location and# geometry is given by 3 lines starting with "PLANE 1". Note that this description# of the fault plane is optional. However, this information is useful in that it# provides a concise description of the fault (e.g. for plotting purposes, etc.).
## The kinematic rupture information begins with the line "POINTS 4", which means this# rupture is represented by 4 subfaults. The detailed description of the rupture on# each subfault follows this line. Note that each subfault has a single slip-rate# function with the direction of slip (rake) varying from subfault to subfault.
## Other useful information that might be included in these comment lines is documentation# of the source of the rupture e.g.,##"Example 2a is a sample rupture scenario generated Mon Nov 24 11:50:22 PST 2014#
with the code "genslip-v3.3.2" (Robert Graves, <rwgraves@usgs.gov>)."## or the usable bandwidth of the rupture, e.g.,##"This rupture is applicable in the bandwidth T>3 sec."#
PLANE 1-119.0985
35.0140
22
16.00
12.00
9540
3.00
-2.00
10.00
POINTS 4-119.1459 34.9826 4.9284 95 40 4.80000e+11 2.6465 1.00000e-01 3.20000e+05 2.65000e+00
828.5960.00
00.00
00.00000e+00 5.91682e+01 1.16849e+01 8.57081e+00 4.81257e+00 1.63265e+00-119.0585 34.9763 4.9284 95 40 4.80000e+11 2.4801 1.00000e-01 3.20000e+05 2.65000e+00
12043.18
70.00
00.00
00.00000e+00 2.88510e+02 5.43680e+01 4.31742e+01 2.83736e+01 1.38752e+01
3.50832e+00-119.1503 34.9414 8.7851 95 40 4.80000e+11 0.0000 1.00000e-01 3.60000e+05 2.75000e+00
76
26.61
20.00
00.00
00.00000e+00 2.66114e+02-119.0629 34.9352 8.7851 95 40 4.80000e+11 0.1637 1.00000e-01 3.60000e+05 2.75000e+00
82118.54
90.0000.00
00.00000e+00 6.18123e+02 2.28298e+02 1.12802e+02 9.21321e+01 6.71185e+01
4.17206e+01 1.99587e+01 5.27757e+00	  	  	  Example	  3:	  Multi-­‐segment	  Rupture	  	  2.0## Example 3a: Multi-segment fault rupture (3 segments).
## This rupture consists of 3 planar rectangular segments. Following these comment lines,# a description of the location and geometry of the individual fault segments is given by# 7 lines starting with "PLANE 3"; 2 lines for each of the 3 fault segments. Note that# this description of the fault segments is optional. However, this information is useful in# that it provides a concise description of the fault (e.g. for plotting purposes, etc.).
## The kinematic rupture information for each segment begins with a line "POINTS <NP>".
# There are 3 of these in this file, one for each segment, and the detailed subfault# information for each segment follows the "POINTS <NP>" line. The number of subfaults# (<NP>) can be different for each segment (<NP>= 4, 6, 8, respectively for the# 3 segments in this file).
## Other useful information that might be included in these comment lines is documentation# of the source of the rupture e.g.,##"Example 3a is a sample rupture scenario generated Mon Nov 24 12:19:29 PST 2014#
with the code "genslip-v3.3.2" (Robert Graves, <rwgraves@usgs.gov>)."## or the usable bandwidth of the rupture, e.g.,##"This rupture is applicable in the bandwidth T>8 sec."#
PLANE 3-119.0985
35.0140
22
16.00
12.00
9540
3.00
-2.00
10.00
-118.9582
35.1398
3230.00
18.00
49800.00-15.0010.00-118.6702
35.2318
42
20.00
15.00
21075
0.00
10.00
12.00
POINTS 4-119.1459 34.9826 4.9284 95 40 4.8000e+11 3.9808 5.00000e-01 -1.00000e+00 -1.00000e+00
90
78.56
30.00
00.00
00.00000e+00 1.15372e+02 4.17567e+01-119.0585 34.9763 4.9284 95 40 4.8000e+11 3.9946 5.00000e-01 -1.00000e+00 -1.00000e+00
94
124.7630.00
00.00
00.00000e+00 1.86001e+02 6.35258e+01-119.1503 34.9414 8.7851 95 40 4.8000e+11 0.0000 5.00000e-01 -1.00000e+00 -1.00000e+00
20248.43
20.00
00.00
00.00000e+00 4.96865e+02-119.0629 34.9352 8.7851 95 40 4.8000e+11 4.6669 5.00000e-01 -1.00000e+00 -1.00000e+00
115
0.00
00.00
00.00
0POINTS 6-118.9772 35.0207 4.4316 49 80 9.0000e+11 8.5605 5.00000e-01 -1.00000e+00 -1.00000e+00
581.2130.00
00.00
00.00000e+00 1.06553e+02 5.58618e+01-118.8944 35.0797 4.4316 49 80 9.0000e+11 11.7304 5.00000e-01 -1.00000e+00 -1.00000e+00-11102.76
30.00
00.00
00.00000e+00 1.44288e+02 6.12220e+01-118.8115 35.1386 4.4316 49 80 9.0000e+11 16.1476 5.00000e-01 -1.00000e+00 -1.00000e+00
761.2820.00
00.00
00.00000e+00 1.22558e+02-118.9659 35.0102 13.2949 49 80 9.0000e+11 6.0000 5.00000e-01 -1.00000e+00 -1.00000e+00-48
302.3040.00
00.00
00.00000e+00 3.70640e+02 2.02352e+02 3.16073e+01-118.8831 35.0691 13.2949 49 80 9.0000e+11 12.2177 5.00000e-01 -1.00000e+00 -1.00000e+00-140.00
00.00
00.00
0-118.8002 35.1280 13.2949 49 80 9.0000e+11 14.2068 5.00000e-01 -1.00000e+00 -1.00000e+00
60
130.1020.00
00.00
00.00000e+00 2.60198e+02
POINTS 8-118.6980 35.3227 3.6222 210 75 3.7500e+11 24.2740 5.00000e-01 -1.00000e+00 -1.00000e+00
5262.6230.00
00.00
00.00000e+00 8.55161e+01 3.97197e+01(continued on next page)

-118.7255 35.2838 3.6222 210 75 3.7500e+11 20.3903 5.00000e-01 -1.00000e+00
73259.66
60.00
00.0000.00000e+00 3.57517e+02 7.02898e+01 5.18295e+01 2.94211e+01 1.02659e+01-118.7530 35.2449 3.6222 210 75 3.7500e+11 20.5304 5.00000e-01 -1.00000e+00
5889.3230.00
00.00
00.00000e+00 1.20825e+02 5.78088e+01-118.7805 35.2060 3.6222 210 75 3.7500e+11 18.2282 5.00000e-01 -1.00000e+00
22173.57
40.00
00.00
00.00000e+00 2.04059e+02 1.03183e+02 3.98911e+01-118.7165 35.3314 10.8667 210 75 3.7500e+11 21.5693 5.00000e-01 -1.00000e+00
90138.38
20.00
0
0.00
00.00000e+00 2.76766e+02-118.7440 35.2925 10.8667 210 75 3.7500e+11 20.7451 5.00000e-01 -1.00000e+00
45
77.84
20.00
00.00
00.00000e+00 1.55686e+02-118.7715 35.2536 10.8667 210 75 3.7500e+11 18.3628 5.00000e-01 -1.00000e+00-15
102.1330.00
00.00
00.00000e+00 1.33963e+02 7.02981e+01-118.7990 35.2147 10.8667 210 75 3.7500e+11 18.0000 5.00000e-01 -1.00000e+00
35
0.00
00.00
00.00
0	  -1.00000e+00-1.00000e+00-1.00000e+00-1.00000e+00-1.00000e+00-1.00000e+00-1.00000e+00